Get in Saudi Arabia
Saudi Arabia has some of the most restrictive travel policies in the world, and advance visas are required for all foreigners desiring to enter. The only significant exception is citizens of the Gulf Cooperation Council nations. Also exempt from visa requirements are foreigners transiting through airports for less than eighteen hours, but many other entry requirements, such as the dress code and restrictions on unaccompanied females, still apply. Nationals of Israel and those with evidence of visiting Israel will be denied visas, although merely being Jewish in and of itself is not a disqualifying factor. (There are, however, anecdotal reports of would-be visitors who tick the “Jewish” or “Atheist” boxes on their visa application having trouble.) Saudis prefer not to grant visas to unaccompanied women, but work permits are common in some fields — esp. nurses, teachers, maids — and possible for anyone if your sponsor has enough connections.
Authorized tour operators
The following five companies are (were?) the only ones authorized to issue tourist visas for Saudi:
Jawlah Tours Company 
Altayyar Group 
Top Adventure Tours 
Samallaghi Tours 
Al Shitaiwi Tours 
Tourist visas, previously available for groups of at least four on guided tours, were “suspended” in late 2010 with vague promises of being reinstated at an unspecified later date; check with a tour company for the latest scoop. Transit visas are limited to some long-distance truck drivers and for plane trips, but are generally issued free of charge. However, it is relatively easy to obtain a transit visa to drive through Saudi if you are legally physically present in an adjacent country and demonstrate the need to drive through Saudi to another adjacent country. Hajj (pilgrimage) visas are issued by the Saudi government through Saudi embassies around the world in cooperation with local mosques. Hajjis and those on transit visas are prohibited from traveling freely throughout the kingdom, and during Hajj season getting a visa of any kind tends to be more difficult. Most short-term Western visitors to Saudi arrive on business visas, which require an invitation from a local sponsor which has been approved by the Saudi Chamber of Commerce. Once this invitation is secured and certified, the actual process of issuing the visa is relatively fast and painless, taking anything from one day to two weeks. Word has it that the “new visas” (electronically generated) are only available through agencies within your country of residence. Getting a work visa is considerably more complex, but usually your employer will handle most of the paperwork.
The fun doesn’t end when you get the visa, since visas do not state their exact expiry date. While the validity is noted in months, these are not Western months but lunar months, and you need to use the Islamic calendar to figure out the length: a three-month visa issued on “29/02/22″ (22 Safar 1429, 1 March 2008) is valid until 29/05/22 (22 Jumada al-Awwal 1429, 28 May 2008), not until 1 June 2008! Depending on visa type, the validity can start from the date of issue or the date of first entry, and multiple-entry visas may also have restrictions regarding how many days at a time are allowed (usually 28 days per visit) and/or how many days total are allowed during the validity period. This all results in fantastic confusion, and it’s not uncommon to get different answers from an embassy, from your employer and from Immigration!
If you have a work visa, exit visas are required to leave the country. (Business, tourism, transit, or Hajj visas do not require exit permits.) You cannot get an exit visa without a signature from your employer, and there have been cases of people unable to leave because of controversy with employers or even customers. For example, if a foreign company is sued in Saudi for non-payment of debts and you are considered its representative, an exit visa may be denied until the court case is sorted out.
Saudi Arabia has very strict rules for what may be imported: alcoholic beverages, pork, non- Sunni Islamic religious materials and pornography (very widely defined) are all prohibited. Computers, VCR tapes and DVDs have all been seized from time to time for inspection by the authorities. If you are unsure if the movie you watch or the video game you play is deemed un-Islamic, it would probably be best not to bring them with you to the kingdom. In general, though, inspections aren’t quite as thorough as they used to be and while bags are still x-rayed, minute searches are the exception rather than the rule. Note that western families driving through on a valid transit visa are generally waved through the customs inspection.
Saudi Arabia has 4 international airports at Riyadh, Jeddah, Madinah ,and Dammam . The airport at Dhahran is now closed to civil traffic, so passengers to the Eastern Region now fly into Dammam, or into nearby Bahrain (which is much better connected) and then cross into Saudi Arabia by car.
Saudi Arabia is served by the national airline Saudi Arabian Airlines , often referred to by its Arabic name Saudia. Saudia has a reasonable safety record, but many of their planes are on the old side and the quality of service, inflight entertainment etc tends to be low. Virtually all Gulf airlines and most major European airlines fly into Saudi. During the Hajj, numerous charter flights supplement the scheduled airlines.
Foreigners living in Saudi Arabia can often get sensational discounts on outbound flights during the Hajj. Airlines from Muslim countries are flying in many loads of pilgrims, and do not want to go back empty.
SAPTCO  operates cross-border bus services to most of Saudi Arabia’s neighbors and even beyond to e.g. Cairo.
Probably the most popular service is between Dammam/Khobar and Bahrain, operated by the separate Saudi-Bahraini Transport Company (SABTCO) . There are five services daily at a cost of SR50/BD5 and the trip across the King Fahd Causeway takes around two hours on a good day; see Bahrain for details.
Automobile crossings exist on nearly all the borders, although those into Iraq are currently closed. The eastern crossings to Bahrain, Qatar and the UAE are heavily used, all others rather less so. There is currently no land border crossing with Oman; plans are in place to open the first such crossing by the end of 2012.
There are no railroads connecting Saudi Arabia with other countries, although in the North, you can still find bits and pieces of the Hejaz Railway that once led to Damascus.
Infrequent passenger ferries run once a week or less from Egypt and Sudan to ports in western Saudi Arabia. (The service to Eritrea has stopped running.) Slow, uncomfortable and not particularly cheap, these are of interest primarily if you absolutely need to take your car across. An unofficial ban on Western travelers may still apply.